1. Field of the Invention
The present invention relates to a light beam irradiation (or heating) apparatus and a method for use in local heat-processing wherein light from a light source is condensed by a reflector. The apparatus and method according to the present invention are particularly useful in heating for local soldering, local removal of a film coated on a thin wire of polyurethane, local heat-processing for resins, or the like.
2. Description of the Prior Art
An apparatus for performing local heating is conventionally known wherein light from a light emitting lamp as a light source is condensed by a reflector and is directly applied to a local area of an object.
The light condensed by the reflector spreads to some extent because the light source itself is not an ideal point light source or for to other reasons. For example, when a xenon lamp is used as a light emitting lamp, it has a spread of about 5 mm in diameter even at a location (beam waist) where light therefrom is throttled to the utmost. The distribution of light energy at the beam waist is not uniform. If heating, for example soldering, is performed using light having a non-uniform energy distribution, solder in the area receiving the light beam is not uniformly fused, thereby producing unevenness in its finish.
FIG. 1 depicts a conventionally known fiber cable accommodating a bundle of optical fibers. As shown in FIG. 1, all the optical fibers are arrayed in parallel with one another. This fiber cable is in wide practical use today but is disadvantageous in that the distribution of light energy is not uniform, as discussed later.
In the meantime, light energy required for heat-processing large quantities or resin or the like is less than that required in soldering. Accordingly, the level of light energy to be irradiated must be lowered, thus reducing the utilization of the light beam irradiation apparatus.
When light beam irradiation is utilized in soldering at high temperatures or in removing a film coated on a wire of polyurethane, not only the amount of whole energy to be irradiated but also the energy density at the center is required to be enlarged. However, it has been impossible to accomplish this so far without enlarging the capacity of the light emitting lamp.